This watchdog blog, by journalist Norman Oder, offers analysis, commentary, and reportage about the $4.9B project to build the Barclays Center arena and 15-16 towers at a crucial site in Brooklyn. Dubbed Atlantic Yards by developer Forest City Ratner in 2003, it was rebranded Pacific Park Brooklyn in 2014 after the Chinese government-owned Greenland Group bought a 70% stake going forward. As of 2018, after the arena and four towers were built, Greenland owns 95% of future construction.

Forest City promotes arena, prefab to Forum for Urban Design; will the arena "begin the substantial and divisive redevelopment" of neighborhoods nearby?

Atlantic Yards builders have recently been promoting the project to the Forum for Urban Design, an organization that "convenes the world’s preeminent leaders in architecture, urban planning,
design and development -- as well as professionals in government,
education and journalism whose work intersects with the built
environment -- to discuss and debate the defining issues that face our
cities."

On April 18, the Forum for Urban Design convened to discuss the tallest building in the world to be built with modular construction. Bruce Ratner and MaryAnne Gilmartin of Forest City Ratner and Christopher Sharples of SHoP Architects presented their ambitious 32 story prefab tower at Atlantic Yards.
Although modular construction has been experimented with for a century, few high-rises have been built using the technique. The latest, built outside of London, reaches twenty-five stories using precast concrete. The first tower of the Atlantic Yards project, B2, will reach seven stories higher, and will be the first with a steel structure.
Ms. Gilmartin and Mr. Sharples explained that B2 would act as Architecture R&D (Research & Development), the first of a dozen or so towers to experiment with modular construction. Devised during the deep recession and amidst vehement community opposition, the prefab towers at Atlantic Yards will accomplish two things: shortened construction time (an estimated six to eight months) and lower construction costs. And with a dozen towers in the works at Atlantic Yards, the process could only become more efficient as each tower is completed.
Mr. Ratner and Mr. Sharples are hopeful that prefab towers could very well become a fixture in major cities across the United States. But only after completing B2 will they know for sure.

The "vehement community opposition" predates the recession; the implication appears to be that shortened construction time would have less of a community impact. Unmentioned is how this process, by lowering construction costs, would upend promises Forest City Ratner made to construction unions.

Three months leading up to its inauguration by Jay-Z, the Forum hosted a tour with Forest City Ratner of the Barclays Center, the arena at the heart of the Atlantic Yards project in Downtown Brooklyn. Winthrop Hoyt, Assistant Vice President of Development in charge of the arena project, sorted through the project’s history, from the Gehry master plan through the new arena design by SHoP Architects to its scheduled completion at the end of September 2012.
Aside from the challenges of building a 15,000 seat arena in an urban setting, the Barclays Center had the added hurdles of the New York MTA and the LIRR, subway and commuter rails that required approval at every step of the process. Additionally, the incredible difficulty of building an arena in a lukewarm economic climate required a more affordable construction process. SHoP Architects managed to pick up the project and accomplish both, with prefabricated steel cladding and a scheme for retractable seating that would allow for versatile uses with a far smaller footprint.
Upon its completion in September 2012, the Barclays Center will be a cornerstone project in the evolving cultural infrastructure of Brooklyn, as well as a new icon for Downtown Brooklyn. Although the housing component of the Atlantic Yards will not be completed for several more years, the arena will likely begin the substantial and divisive redevelopment of the Prospect Heights and Fort Greene neighborhoods.

The arena's about 18,000 seats for basketball, potentially more (but often less) for other events, depending on the size of the stage and the importance of 360-degree views. Actually, "retractable seating" hasn't been mentioned much. The New York Times reported in January, regarding plans for hockey:

Retractable seats will mostly be collapsed on one end, closest to the
Atlantic Terminal side, and therefore the alignment around the rink will
resemble a horseshoe.

Will the arena "likely begin the substantial and divisive redevelopment of the Prospect Heights and Fort Greene neighborhoods"? I think the "substantial" part already happened. The "divisive" part, surely, was accelerated by the announcement of Atlantic Yards.

As for "several more years," it's a real wildcard.

The "incredible difficulty of building and arena in a lukewarm economic climate" should be counterbalanced by the significant opportunity for sponsorships and publicity in the nation's media market.